Kanban in software development starts with David Anderson’s book. It’s heavy on selling the ideas behind Kanban, but unfortunately light on facts and examples – mostly because there wasn’t a lot of experience and data to draw on at the time the book was written. Everything is built up from two case studies in small maintenance organizations.

The first case study (which you can read here online) goes back to 2005, at a small offshore sustaining engineering team in Microsoft. This team couldn’t come close to keeping up with demand, because of the insanely heavyweight practice framework that they were following (CMMI and TSP/PSP) and all of the paperwork and wasted planning effort that they were forced to do. They were spending almost half of their time on estimating and planning, and half of this work would never end up being delivered because more work was always coming in.

Anderson and another Microsoft manager radically simplified the team’s planning, prioritization and estimation approach, cutting out a lot of the bullshit so that the team could focus instead on actually delivering what was important to the customers.

You can skip over the theory – the importance of Drum-Buffer-Rope – Anderson changed his mind later on the theory behind the work anyways. As he says:

“This is a case study about implementing common sense changes where they were needed”.

The second case study is about Anderson doing something similar with another ad hoc maintenance team at Corbis a couple of years later. The approach and lessons were similar, in this case focusing more on visual tracking of work and moving away from time boxing for maintenance and break/fix work, using explicit WIP limits instead as the forcing function to control the team’s work.

The rest of the book goes into the details of tracking work on task boards, setting and adjusting limits, and just-in-time planning. There’s also some discussion of effecting organizational change and continuous improvement, which you can get from any other Agile/Lean source.

Corey Ladas’ book Scrumban is a short collection of essays on Kanban and combining Scrum and Kanban. The book is essentially built around one essay, which, taking a Lean approach to save time and money, I suggest that you read here instead. You don’t need to bother with the rest of the book unless you want to try and follow along as Ladas works his ideas out in detail. The basic ideas are the same as Anderson (not surprising, since they worked together at Corbis):

Don’t build features that nobody needs right now.
Don’t write more code than you can test.
Don’t test more code than you can deploy.

David Anderson has a new book on Kanban coming out soon Unfortunately it looks like a rehash of some of his blog posts with updated commentary. I was hoping for something with more case studies and data, and follow-ups on the existing case studies to see if they were able to sustain their success over time.

There is other writing on Kanban, by excited people who are trying out (often in startups or small teams), or by consultants who have added Kanban to the portfolio of what they are selling – after all, “Kanban is the New Scrum”.

You can keep up with most of this through the Kanban weekly Roundup, which provides a weekly summary of links and discussion forums and news groups and presentations and training in Kanban and Lean stuff. And there’s a discussion group on Kanban development which is also worth checking out. But so far I haven’t found anything, on a consistent basis anyways, that adds much beyond what you will learn from reading Anderson’s first Kanban book.

Where does Kanban work best?

Kanban was created to help break/fix maintenance and sustaining engineering teams. Kanban’s pull-based task-and-queue work management matches the unpredictable, interrupt-driven and specialized work that these teams do. Kanban puts names and a well-defined structure around common sense ideas that most successful maintenance and support and operations teams already follow, which should help inexperienced teams succeed. It makes much more sense to use Kanban than to try to bend Scrum to fit maintenance and support, or following a heavyweight model like IEE 1219 or whatever it is being replaced by.

I can also see why Kanban has become popular with technology startups, especially web / SaaS startups following Continuous Deployment and a Lean Startup model. Kanban is about execution and continuous optimization, removing bottlenecks and reducing cycle time and reacting to immediate feedback. This is exactly what a startup needs to do once they have come up with their brilliant idea.

But getting control over work isn’t enough, especially over the longer-term. Kanban’s focus is mostly tactical, on the work immediately in front of the team, on identifying and resolving problems at a micro-level. There’s nothing that gets people to put their heads up and look at what they can and should do to make things better on a larger-scale – before problems manifest themselves as delays. You still need a layer of product management and risk management over Kanban, and you’ll also need a technical software development practice framework like XP.

I also don’t see how – or why – Kanban makes much of a difference in large-scale development projects, where flow and tactical optimization aren’t as important as managing and coordinating all of the different moving pieces. Kanban won’t help you scale work across an enterprise or manage large programs with lots of interdependencies. You still have to do project and program and portfolio management and risk management above Kanban’s micro-structure for managing day-to-day work, and you still need a SDLC.

“Kanban is not a software development life cycle or a project management methodology…You apply a Kanban system to an existing software development process…”

Kanban can help teams that are being crushed under a heavy workload, especially support and maintenance teams. Combining Kanban with a triage approach to prioritization would be a good way to get through a crisis.

Although some people argue that iterations add too much overhead and slow teams down, you can strip overheads down so that time boxing doesn’t get in the way - so that you really are sprinting.

Getting the team to understand the flow of work, making delays and blockers visible and explicit is an important part of Kanban. But Microsoft’s Eric Brechner (er, I mean, “I. M. Wright”) explains that you don’t need Kanban and taskboards to see delays and bottlenecks or to balance throughput in an experienced development team:

“Good teams do this intuitively to avoid wasted effort. They ‘right-size’ their teams and work collaboratively to succeed together.”

And anybody who is working iteratively and incrementally is already doing or should be doing just-in-time planning and prioritization.

So for us, Kanban doesn’t seem to be worth it, at least for now. If your development team is inexperienced and can’t deliver (or don’t know what they need to deliver), or you’re in a small maintenance or firefighting group, Kanban is worth trying. If Kanban can help operations and maintenance teams survive, and help some online startups launch faster, if that’s all that people ever do with Kanban, the world will still be a better place.

1 comment:

Whey then do we take old manufacturing ideas and try to apply them to software development while retaining the names? Lean, kanban et al were developed for very different contexts than software development, and a lot of other factory and production methods are derided in software circles. I personally find it confusing since I studied a lot of these processes in university in the '90s. Much of what is new in software development sounds a lot like what was being studied and critiqued in the '90s in other fields.

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About Me

I am an experienced software development manager, project manager and CTO focused on hard problems in software development and maintenance, software quality and security. For the last 15 years I have managed teams building and operating high-performance financial systems.
My special interest is how small teams can be most effective in building real software: high-quality, secure systems at the extreme limits of reliability, performance, and adaptability. Software that has to work, that is built right, and built to last.
I use this blog to explore ideas and problems in software development that are important to me. To reflect and to find new answers.